1. Field of the Invention
The invention herein resides in the area of gun sight mounts and more particularly relates to an off-barrel gun sight mount that can be manually adjusted for both range and projectile drift.
2. Description of the Prior Art
MK19 heavy grenade machine guns currently incorporate a fold-up, rear iron sight mounted on the rear of the receiver which sight is utilized in combination with a fixed front sight post mounted at the weapon's midsection at the juncture of the rear of the barrel and the front of the receiver. The current iron sight is adjusted for ranges beyond 300 meters by manually raising its "ladder" member to the desired range marked on its vertical scale which action causes a laterally sliding of an open notch member on the "ladder" member. The open notch is then aligned with the front sight post, and the gun is targeted by the manual manipulation of the weapon. Because of the very high trajectory of 40 mm ammunition at ranges beyond 1500 meters, the barrel of the gun must be elevated considerably; and at distances beyond 1500 meters the end of the barrel obscures the front sight post since it extends upwards in front of the sight post and thus prevents the gunner from sighting with the prior art fold-up iron sight. Since the effective range of the ammunition for the MK19 heavy grenade machine gun is greater than 2000 meters, an improved sight has long been felt desirable for the MK19 heavy grenade machine gun and equivalent guns. Merely extending the height of the "ladder" of the iron sight currently used would not solve the above-mentioned problems since the front sight post is mounted at the weapon's midsection and would have to be relocated to the muzzle end of the barrel. Such movement of the front sight post to the muzzle end of the barrel is impractical since there is no accurate top dead center reference surface, and such movement would further require regraduation and replacement of the current rear iron sight.
Many other different types of sights can also be mounted on MK19 machine guns on a fixed-sight mount placed on the receiver of the gun with such sights directly above and in line with the barrel axis, such as day-night sights, image-intensifier sights, thermal sights, and laser-aiming devices in combination with image-intensifier sights, but these sights, being aligned with the barrel, are also interfered with by the elevation of the barrel at extended ranges and have no effective way for being adjusted for elevation relative to range. Some sights have graduation lines in their eyepieces to indicate various ranges.
Improving the ability of the MK19 heavy grenade machine gun to be properly aimed beyond 1500 meters would significantly enhance its tactical flexibility and provide greater depth of usage in a variety of situations for defensive and offensive operations, resulting in enhanced effectiveness of the crew and weapon.